The present invention relates to a steel laminate gasket, more particularly, a steel laminate gasket properly sealing engine parts having high and non-high pressure areas therein even if the gasket receives a low tightening pressure at the non-high pressure areas.
An internal combustion engine is provided with a large hole for a chain case and small holes for cooling water, push rods and so on as well as cylinder bores for pistons. The engine is formed of a plurality of engine parts connected together by bolts, wherein a gasket is positioned between the two engine parts for sealing therebetween.
Generally, the cylinder bores receive high pressure, but the holes other than the cylinder bores do not receive so high pressure. Therefore, the engine parts are tightened strongly around the cylinder bores, while the other portions of the engine parts are not tightened so strongly. In this respect, the gasket is designed to actuate or work properly by receiving high pressure at portions adjacent the cylinder bores and by receiving non-high pressure at portions away from the cylinder bores.
A conventional steel laminate gasket is provided with sealing materials made of rubber around holes other than the cylinder bores of an engine, an example of which is shown in FIG. 1. Namely, a conventional steel laminate gasket 10 comprises a body portion 11 including an upper plate 12, a lower plate 13, two inner plates 14 and a core material 15, and a rubber ring 16. The core material 15 does not extend to an edge of a hole 17 for liquid, such as a water hole or oil hole, thereby to form a lateral concave 18 around the hole 17. A part of a plate 19 attached to the rubber ring 16 is placed in the concave 18, so that the ring 16 is connected to the body portion of the steel laminate gasket 10.
When the gasket 10 is used, the gasket 10 is placed between two engine parts (not shown) and the engine parts are tightened by bolts (not shown). Consequently, the ring 16 is sandwiched and pushed by the engine parts to thereby seal around the hole 17.
In this conventional steel laminate gasket 10, since the ring 16 is made of rubber, an outer surface of the ring 16 may be cracked or a quality of rubber goes wrong due to a long period of use. Consequently, sealing ability of the ring 16 decreases. In an extreme situation, the ring 16 can not seal properly around a hole of an engine.
Accordingly, one object of the present invention is to provide a steel laminate gasket, which can seal properly in non-high pressure receiving areas as well as high pressure receiving areas.
Another object of the invention is to provide a steel laminate gasket as explained above, which can be efficiently used for a long period of time.
A further object of the invention is to provide a steel laminate gasket as explained above, which can be manufactured economically.
Further objects and advantages of the invention will be apparent from the following description of the invention.